Appeal from the Superior Court of the District of Columbia (CMD20384-08) (Hon. Harold L. Cushenberry, Jr., Trial Judge).
 The opinion of the court was delivered by: Fisher, Associate Judge
 Submitted April 15, 2010
 Before FISHER, Associate Judge, and KERN and KING, Senior Judges.
 Appellant challenges his conviction, after a bench trial, for possession of heroin, arguing that the trial court committed reversible error when it denied his mid-trial request to withdraw his express waiver of the right to confront a government chemist. Finding no abuse of discretion, we affirm.
 I. Statement of Facts
 On August 12, 2008, appellant was approached by Officer David Wildey of the Metropolitan Police Department, who, after searching the right pocket of appellant's cargo shorts, found two small zip-lock bags, each containing a tan powder substance.*fn1 After placing the appellant in handcuffs, Officer Wildey handed the two zip-locks to his partner, Officer Sarah Hoffman, who placed them into a heat seal, the PD-95. Appellant's name and the place from which the zip-locks were recovered (appellant's right-leg cargo pocket) were written on the PD-95. Officer Hoffman field tested one of the bags, which tested positive for opiates, but she could not recall whether she did that on the scene or at the station. Appellant was subsequently charged with, and convicted of, possessing heroin, in violation of D.C. Code § 48-904.01 (d) (2001).
 On the day before trial, appellant explicitly waived his right to hear testimony from the DEA chemist who analyzed the substance found in the zip-locks. Addressing appellant personally, the court asked, "[Your attorney] indicated that you no longer want the chemist to testify, is that true?" Appellant replied, "Yes, sir." The next morning, before trial began, the court mentioned, without contradiction, that the defendant had "agreed to waive . . . the chemist . . . ."
 The DEA lab number on the heat seal envelope was LV-375.During cross-examination, Officer Hoffman testified that, because of a "slight drag of the pen," the lab number on one of the zip-lock bags inside the heat seal looked as though it might read LV-325, instead of LV-375. She also testified that the letters written on one of the zip-lock bags "actually look[ed] like LU" and that the number "look[ed] like 325." She had not written the lab number and assumed someone at the DEA had done so.
 Shortly thereafter, appellant sought to withdraw his waiver of the DEA chemist's testimony. He argued that, because he had not seen the heat seal before waiving the chemist's appearance, he could not have known of the possible inconsistency between the lab numbers. Appellant argued that the chemist's testimony now was necessary to "explain the difference between the 325 and 375." The trial judge denied the request, explaining that "[t]here's no doubt that these are the same drugs . . . ."
 II. Standard of Review
 Neither party cites, and we have not found, any case law specifically addressing the standard of review we should apply to the denial of appellant's mid-trial request to withdraw his waiver of the right to confront a government chemist. Nevertheless, as the government has pointed out, this court reviews comparable rulings -- denials of mid-trial requests to withdraw a stipulation, denials of motions to withdraw a guilty plea, and denials of motions to withdraw a waiver of the right to a jury trial -- under the abuse of discretion standard. See Byrd v. United States, 485 A.2d 947, 949-50 (D.C. 1984) (stipulation that witness would have testified in a certain fashion; "It is true that trial courts do have discretion to relieve a party from a stipulation where such action is intended to prevent manifest injustice."); Gooding v. United States, 529 A.2d 301, 306 (D.C. 1987) (motions to withdraw guilty pleas "are addressed to the sound discretion of the trial court"); Sparks v. United States, 358 A.2d 307, 311 (D.C. 1976) (waiver of the right to a jury trial; "[T]his court will reverse a lower court's determination to either allow or disallow withdrawal of consent only if there is an abuse of this discretion.").
 An attempt to withdraw a stipulation provides an especially apt analogy since this court has stated that an express waiver of the right to confront a DEA chemist "may . . . take the form of a stipulation by the defendant as to the contents of the chemist's report." Thomas v. United States, 914 A.2d 1, 19 (D.C. 2006). In addition, because the right to contest a factual matter, the right to a trial at which one's guilt must be proven, and the right to trial by jury are no less important than the right to confront a government witness, it is appropriate to apply similar analysis to an attempt to withdraw a waiver of the right at issue here.
 "Discretion signifies choice." (James) Johnson v. United States, 398 A.2d 354, 361 (D.C. 1979). Moreover, "[t]he concept of 'exercise of discretion' is a review-restraining one"; our "role . . . is supervisory in nature and deferential in attitude." Id. at 362 (internal citations omitted). Consequently, we do "not render [our] own decision of what judgment is most wise under the circumstances presented," but instead recognize that "the decision-maker exercising discretion has the ability to choose from a range of permissible conclusions." Id. at 361-62. Nevertheless, "[a]n informed choice among the alternatives requires that the trial court's determination be based upon and drawn from a firm factual foundation." Id. at 364. In addition, when "reviewing the decision for an abuse of discretion [we] must determine whether the decision maker failed to consider a relevant factor, whether he relied upon an improper factor, and whether the reasons given reasonably support the conclusion." Id. at 365 (internal ...